"James had a magnificent tournament for the Republic of Ireland last summer during UEFA EURO 2016, playing his last game in very late June. He then returned to Everton after a very short break, but only 11 days later, he played his first of three games, all within an eight-day period, against Real Betis, Manchester United and Espanyol. Overloading?

It is not the first time Koeman and O'Neill have had a difference in opinion and it is understood that the Ireland boss tried to contact Everton's counterpart on several occasions before Christmas, but the calls were left unreturned.

Behind the scenes, the FAI is frustrated by what they see as Koeman's unwillingness to talk to them, while the Dutchman has been willing to discuss his concerns with the media.

Koeman is preparing for Saturday's Merseyside derby against Liverpool, live on Sky Sports 1HD, without three of his key players who were injured on international duty, with Argentina's Ramiro Funes Mori and Ireland's Seamus Coleman also sustaining injuries.